In Jr. Pac-Man, protagonist fell in love with a cute ghost girl named Yum-Yum, but her ghostly family refused this relationship and so they imprisoned Junior in a maze and attempted to defeat him, luckily Junior triumphed against the ghost and was able to be with his beloved Yum-Yum.

Jr. Pac-Man first appears in this game in the opening cutscene. He is seen walking to his dad's 20th birthday. When he's about to open the door, a small robot (from the Golden Fruit Smoothie Factory area, the fifth area on Ghost Island) sneaks up behind him, and extends a huge claw from itself and takes Junior's hat. Junior notices this, and turns around, confused. He sees it's just a cute little robot, and turns back to open the door. Then the robot once again extends his claw, and this time grabs Junior, and shoves him into it's insides. The robot then scuttles off. Jr. is later seen in the 18th level, Down The Tubes in the Golden Fruit Smoothie Factory area. He is seen in a huge cage, on a platform above a huge pool. Once Pac-Man goes through a lot of trouble to get the Key, he frees Jr., and Jr. tells him where the exit is. Jr. later appears in the fight against Toc-Man in the last level, Toc-Man's Lair, along with Pac-Man's other five friends. He assists in the fight by throwing out Health Wedges, along with the other rescued friends.

In this game, Jr. Pac-Man rides a rocket powered skate board. He is the slowest, but the best at turning and has highest at acceleration in the game.

Jr. on his skateboard

Trivia

His first appearance was in a cutscene in the Ms. Pac-Man game. He is delivered to Pac-Man and Ms. Pac-Man by the stork.

In the 2nd season of the 1980s Pac-Man Cartoon, a character known as "PJ" joins the cast. In one episode he states his full name as "Pac Junior". But PJ is actually the nephew of the titular hero. Pac-Baby in the cartoon, however is a closer analogue to Pac-Man Junior from the game.

While not explicitly stated, the character we know as Pac-Man Jr. was likely the original Baby Pac-Man from the ill-fated pinball / video game hybrid of the same name. He likely became known as Pac-Man Jr when the female version was born, and the Pac-Baby name got handed down to her.

In different games, the appearance of Jr. Pac-Man's skateboard varies.